Pretty is used to tone down a statement and is in wide use across the whole spectrum of english A pretty little cabin in the woods. It is common in informal speech and writing but is neither rare nor wrong in serious discourse.
Pleasing or attractive to the eye, as by delicacy or gracefulness. Pleasing or charming but not grand or overwhelming See examples of pretty used in a sentence.
… that's a pretty hat you're wearing The sofa was covered in very pretty flowery material She's got such a pretty daughter She looked pretty in a simple cotton dress.
When particularly stressed, the adverb pretty serves almost to diminish the adjective or adverb that it modifies, by emphasizing that there are greater levels of intensity. In a delicate or graceful way
